Known securing mechanisms for releasably securing a drainage element to a press are used in universal fruit presses, in which the press contains a press container or receptacle which is rotatable about a horizontal axis, a press plate, and a counter-press plate which are disposed at right angles to a horizontal axis opposite one another. A press-space is defined between the press plate and the counter-press plate, and a plurality of longitudinal flexible drainage elements, each releasably connectable to the press plate and the counter-press plate, extend between the press plates through passages provided in the press plates. For example, in a press having a capacity of approximately 5000 kg of mash, there are provided about 220 of such flexible drainage elements. As a rule each drainage element consists of a void-like flexible core of rubber or similar flexible material, and wherein the core is provided on its circumference with longitudinal grooves extending in an axial direction, and a liquid-permeable sleeve surrounding the core which preferably consists of textile material. The known securing mechanism anchors the core together with the stocking-like sleeve to the press plate, so that the drainage elements are under slight tension in an axial direction, when the press plates are remote from one another, while they are disposed loosely in the mash when the press plates are disposed close to one another as a result of the mash being squeezed by the press plates.
In the known securing mechanism the securing sleeve is provided with a thread in the region of the circumference of a a collar surrounding the sleeve and bordering a radially extending flange, and wherein the threaded sleeve may be threaded into a female thread provided in a passage of the press-plate up to a region where the radially extended flange is located. The inner circumference of the securing sleeve or collar has a shape of a truncated female cone within a region where the securing sleeve or collar extends through the passage in the press plate to a fluid-receiving chamber from the radially extending flange up to the free end of the collar facing the fluid-receiving chamber. A similarly formed matching cone consisting of two portions is provided near the free end of each drainage element, in such a way that below the liquid-permeable sleeve a rubber sleeve surrounds the flexible core as a first portion, and that there is provided a rigid supporting truncated cone which abuts the rubber sleeve, and which is secured to the core as a second portion. By the engagement of the truncated cone disposed on the inner periphery of the securing sleeve with the truncated cone secured to the drainage element, the drainage element is anchored to the press plate by means of the securing sleeve being threaded to the press plate through the passage in the press plate, so that the liquid-permeable sleeve is clamped between the two truncated cones.
Although this known securing mechanism fulfills the function assigned thereto, namely to discharge the fluid obtained from the press along the grooved channels of the drainage element through the passage in the press-plate to the fluid-receiving channel in a satisfactory manner, it nevertheless has disadvantages concerning the method of securing the drainage element to the press-plate and releasing it therefrom. These disadvantages are due to the fact that, on one hand, it is very time-consuming to thread the 220 to 440 securing mechanisms to to the press plate, and, on the other hand, due to too much force being required for this task. Additionally during securing of the drainage-element to press-plates there occurs the risk that during threading of the securing sleeve any tool used therefor, for example, a fork wrench, or spanner engaging the flange of the securing sleeve from the side of the press-space, that fork wrench or spinner may slide off therefrom, which can result in damage to the liquid-permeable sleeve of the drainage element.
Furthermore, the relatively small distance between the individual securing mechanisms requires the use of a special tool. This does not, however, preclude the tool engaging the securing-sleeve from jamming, which further impairs the installation of the drainage elements.
Finally, after the drainage element is threaded into the corresponding female thread of the press-plate it is a considerable disadvantage that the increasing friction between the two matching male and female cones may lead to a twisting of the sleeve clamped therebetween with respect to the inner core. In order to avoid such a twist, the sleeve must be rotated several turns prior to threading of the securing sleeve into the press plate, so that one obtains at most only a negligible twist of the sleeve itself. These special precautions prolong the installation, without ensuring that the sleeve may not be damaged by the two cones.